K8S-学习笔记-快速部署kubernetes集群的工具

左手的ㄟ右手 2023-10-11 18:35 6阅读 0赞

kubeadm是官方社区推出的一个用于快速部署kubernetes集群的工具。

这个工具能通过两条指令完成一个kubernetes集群的部署：

# 创建一个 Master 节点
    $ kubeadm init
    
    # 将一个 Node 节点加入到当前集群中
    $ kubeadm join <Master节点的IP和端口 >

### 1. 安装要求 ###

在开始之前，部署Kubernetes集群机器需要满足以下几个条件：

*  一台或多台机器，操作系统 CentOS7.x-86\_x64
 *  硬件配置：2GB或更多RAM，2个CPU或更多CPU，硬盘30GB或更多
 *  可以访问外网，需要拉取镜像，如果服务器不能上网，需要提前下载镜像并导入节点
 *  禁止swap分区

### 2. 准备环境 ###

<table> 
 <thead> 
  <tr> 
   <th>角色</th> 
   <th>IP</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>master</td> 
   <td>192.168.10.40</td> 
  </tr> 
  <tr> 
   <td>node1</td> 
   <td>192.168.10.41</td> 
  </tr> 
  <tr> 
   <td>node2</td> 
   <td>192.168.10.42</td> 
  </tr> 
 </tbody> 
</table>

# 关闭防火墙
    systemctl stop firewalld
    systemctl disable firewalld
    
    # 关闭selinux
    sed -i 's/enforcing/disabled/' /etc/selinux/config  # 永久
    setenforce 0  # 临时
    
    # 关闭swap
    swapoff -a  # 临时
    sed -ri 's/.*swap.*/#&/' /etc/fstab    # 永久
    
    # 根据规划设置主机名
    hostnamectl set-hostname <hostname>
    
    # 在master添加hosts
    cat >> /etc/hosts << EOF
    192.168.10.40 k8smaster
    192.168.10.41 k8snode1
    192.168.10.42 k8snode2
    EOF
    
    # 将桥接的IPv4流量传递到iptables的链
    cat > /etc/sysctl.d/k8s.conf << EOF
    net.bridge.bridge-nf-call-ip6tables = 1
    net.bridge.bridge-nf-call-iptables = 1
    EOF
    sysctl --system  # 生效
    
    # 时间同步
    yum install ntpdate -y
    ntpdate time.windows.com

### 3. 所有节点安装Docker/kubeadm/kubelet ###

Kubernetes默认CRI（容器运行时）为Docker，因此先安装Docker。

#### 3.1 安装Docker ####

$ wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
    $ yum -y install docker-ce-18.06.1.ce-3.el7
    $ systemctl enable docker && systemctl start docker
    $ docker --version
    Docker version 18.06.1-ce, build e68fc7a

$ cat > /etc/docker/daemon.json << EOF
    {
      "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
    }
    EOF

#### 3.2 添加阿里云YUM软件源 ####

$ cat > /etc/yum.repos.d/kubernetes.repo << EOF
    [kubernetes]
    name=Kubernetes
    baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
    enabled=1
    gpgcheck=0
    repo_gpgcheck=0
    gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
    EOF

#### 3.3 安装kubeadm，kubelet和kubectl ####

由于版本更新频繁，这里指定版本号部署：

$ yum install -y kubelet-1.18.0 kubeadm-1.18.0 kubectl-1.18.0
    $ systemctl enable kubelet

### 4. 部署Kubernetes Master ###

在192.168.10.40（Master）执行。

$ kubeadm init \
      --apiserver-advertise-address=192.168.10.40 \
      --image-repository registry.aliyuncs.com/google_containers \
      --kubernetes-version v1.18.0 \
      --service-cidr=10.96.0.0/12 \
      --pod-network-cidr=10.244.0.0/16

由于默认拉取镜像地址k8s.gcr.io国内无法访问，这里指定阿里云镜像仓库地址。

会在初始化日志看到类似以下日志

Your Kubernetes control-plane has initialized successfully!
    
    To start using your cluster, you need to run the following as a regular user:
    
    # master 节点中执行
    mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config
    
    You should now deploy a pod network to the cluster.
    Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
      https://kubernetes.io/docs/concepts/cluster-administration/addons/
    
    Then you can join any number of worker nodes by running the following on each as root:
    
    ## node 节点中执行次脚本
    kubeadm join 192.168.10.40:6443 --token suot1a.2yc0ddeht4o1pywy \
        --discovery-token-ca-cert-hash sha256:d3aba48d11771ccaf09d55ebcb109be4e838edf0716ff1c23ad4c9c6be968868

使用kubectl工具：

mkdir -p $HOME/.kube
    sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
    sudo chown $(id -u):$(id -g) $HOME/.kube/config
    $ kubectl get nodes

### 5. 加入Kubernetes Node ###

在192.168.1.41/42（Node）执行。

向集群添加新节点，执行在kubeadm init输出的kubeadm join命令：

$ kubeadm join 192.168.10.40:6443 --token esce21.q6hetwm8si29qxwn \
        --discovery-token-ca-cert-hash sha256:00603a05805807501d7181c3d60b478788408cfe6cedefedb1f97569708be9c5

默认token有效期为24小时，当过期之后，该token就不可用了。这时就需要重新创建token，操作如下：

kubeadm token create --print-join-command

### 6. 部署CNI网络插件 ###

wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

默认镜像地址无法访问，sed命令修改为docker hub镜像仓库。

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
    
    kubectl get pods -n kube-system
    NAME                          READY   STATUS    RESTARTS   AGE
    kube-flannel-ds-amd64-2pc95   1/1     Running   0          72s

kube-flannel.yml

---
    kind: Namespace
    apiVersion: v1
    metadata:
      name: kube-flannel
      labels:
        pod-security.kubernetes.io/enforce: privileged
    ---
    kind: ClusterRole
    apiVersion: rbac.authorization.k8s.io/v1
    metadata:
      name: flannel
    rules:
    - apiGroups:
      - ""
      resources:
      - pods
      verbs:
      - get
    - apiGroups:
      - ""
      resources:
      - nodes
      verbs:
      - list
      - watch
    - apiGroups:
      - ""
      resources:
      - nodes/status
      verbs:
      - patch
    ---
    kind: ClusterRoleBinding
    apiVersion: rbac.authorization.k8s.io/v1
    metadata:
      name: flannel
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: ClusterRole
      name: flannel
    subjects:
    - kind: ServiceAccount
      name: flannel
      namespace: kube-flannel
    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: flannel
      namespace: kube-flannel
    ---
    kind: ConfigMap
    apiVersion: v1
    metadata:
      name: kube-flannel-cfg
      namespace: kube-flannel
      labels:
        tier: node
        app: flannel
    data:
      cni-conf.json: |
        {
          "name": "cbr0",
          "cniVersion": "0.3.1",
          "plugins": [
            {
              "type": "flannel",
              "delegate": {
                "hairpinMode": true,
                "isDefaultGateway": true
              }
            },
            {
              "type": "portmap",
              "capabilities": {
                "portMappings": true
              }
            }
          ]
        }
      net-conf.json: |
        {
          "Network": "10.244.0.0/16",
          "Backend": {
            "Type": "vxlan"
          }
        }
    ---
    apiVersion: apps/v1
    kind: DaemonSet
    metadata:
      name: kube-flannel-ds
      namespace: kube-flannel
      labels:
        tier: node
        app: flannel
    spec:
      selector:
        matchLabels:
          app: flannel
      template:
        metadata:
          labels:
            tier: node
            app: flannel
        spec:
          affinity:
            nodeAffinity:
              requiredDuringSchedulingIgnoredDuringExecution:
                nodeSelectorTerms:
                - matchExpressions:
                  - key: kubernetes.io/os
                    operator: In
                    values:
                    - linux
          hostNetwork: true
          priorityClassName: system-node-critical
          tolerations:
          - operator: Exists
            effect: NoSchedule
          serviceAccountName: flannel
          initContainers:
          - name: install-cni-plugin
           #image: flannelcni/flannel-cni-plugin:v1.1.0 for ppc64le and mips64le (dockerhub limitations may apply)
            image: docker.io/rancher/mirrored-flannelcni-flannel-cni-plugin:v1.1.0
            command:
            - cp
            args:
            - -f
            - /flannel
            - /opt/cni/bin/flannel
            volumeMounts:
            - name: cni-plugin
              mountPath: /opt/cni/bin
          - name: install-cni
           #image: flannelcni/flannel:v0.19.2 for ppc64le and mips64le (dockerhub limitations may apply)
            image: docker.io/rancher/mirrored-flannelcni-flannel:v0.19.2
            command:
            - cp
            args:
            - -f
            - /etc/kube-flannel/cni-conf.json
            - /etc/cni/net.d/10-flannel.conflist
            volumeMounts:
            - name: cni
              mountPath: /etc/cni/net.d
            - name: flannel-cfg
              mountPath: /etc/kube-flannel/
          containers:
          - name: kube-flannel
           #image: flannelcni/flannel:v0.19.2 for ppc64le and mips64le (dockerhub limitations may apply)
            image: docker.io/rancher/mirrored-flannelcni-flannel:v0.19.2
            command:
            - /opt/bin/flanneld
            args:
            - --ip-masq
            - --kube-subnet-mgr
            resources:
              requests:
                cpu: "100m"
                memory: "50Mi"
              limits:
                cpu: "100m"
                memory: "50Mi"
            securityContext:
              privileged: false
              capabilities:
                add: ["NET_ADMIN", "NET_RAW"]
            env:
            - name: POD_NAME
              valueFrom:
                fieldRef:
                  fieldPath: metadata.name
            - name: POD_NAMESPACE
              valueFrom:
                fieldRef:
                  fieldPath: metadata.namespace
            - name: EVENT_QUEUE_DEPTH
              value: "5000"
            volumeMounts:
            - name: run
              mountPath: /run/flannel
            - name: flannel-cfg
              mountPath: /etc/kube-flannel/
            - name: xtables-lock
              mountPath: /run/xtables.lock
          volumes:
          - name: run
            hostPath:
              path: /run/flannel
          - name: cni-plugin
            hostPath:
              path: /opt/cni/bin
          - name: cni
            hostPath:
              path: /etc/cni/net.d
          - name: flannel-cfg
            configMap:
              name: kube-flannel-cfg
          - name: xtables-lock
            hostPath:
              path: /run/xtables.lock
              type: FileOrCreate

### 7. 测试kubernetes集群 ###

在Kubernetes集群中创建一个pod，验证是否正常运行：

$ kubectl create deployment nginx --image=nginx
    $ kubectl expose deployment nginx --port=80 --type=NodePort
    $ kubectl get pod,svc

访问地址：http://NodeIP:Port